That makes sense to me, but again I'm a novice. Do you have a source?
Do a Google search for "Strasbourg Tests". In that test several European police agencies did a test on live French Alpine goats of the same size and weight of the average human male to see which cartridge disabled a healthy goat in the shortest length of time. I think something like 600 goats were shot in the thorax with various popular handgun rounds, and the time interval between the shot and the animal's collapse was recorded to the tenth of a second and averaged out over a series of shots from each cartridge.
IIRC the .45acp did very well, but it wasn't the top "stopper". Again, IIRC, the .357 mag firing a 125 grain hollow point round took the top spot. Also IIRC, the 9mm came in with a very respectable score, not far behind the .45acp in fact.
For me personally I usually carry a Taurus medium frame 2-1/2" .357 revolver in a Don Hume belt slide holster, except in hot weather when I can't conceal it under a jacket or coat. In hot weather I have been carrying a commercial Russian Makarov .380 semiauto loaded with Federal HydroShok cartridges in a pocket holster, but I am planning to upgrade to a 9mm Springfield Armory XD Compact semiauto before summer weather returns. IMHO the .380 is just barely adequate for self defense, but at the time I bought it there were no truly small 9mm guns on the market and it was better than the little .32s.
If I were you I would check out the Springfield compact. It has everything going for it that the Glock model 26 has and it's quite a bit less expensive. Although I really like the old .45acp and have owned several 1911s and one S&W .45acp revolver, I believe anyone is quite well armed carrying a reliable 9mm loaded with good hollow point cartridges such as Corbons or Hydroshoks.
I love caliber wars!!
In general...shot placement is much more important that bullet size. Doesn't really matter how power the cartridge, if you miss the target?
In other words!...A well-placed 9mm. is far superior to a well-missed .45 ACP.
Look at a variety of guns in various caliber’s and frame size. Feel, balance & control will be the deciding factor.